FLEX and Sentinel-3C in Orbit: Leonardo and Telespazio's Contribution to ESA's Earth Observation Missions

15 September 2026

On September 15th 2026, at 03:21 Italian time, the FLEX and Copernicus Sentinel-3C satellites of the European Space Agency (ESA) successfully launched from Europe's Spaceport in Kourou, French Guiana. Both travelled aboard the same launcher, Avio's Vega-C, and are now flying in tandem orbit, spaced roughly ten seconds apart, at an altitude of around 800 kilometres.

The two missions will help observe, with greater precision, the health of vegetation, sea and land surface temperature and the development of wildfires — essential information for studying climate change and protecting ecosystems.

Both satellites carry technology developed by Leonardo at its Campi Bisenzio (Florence) site, while Telespazio is responsible for key mission control and operations activities.

FLEX: Observing Photosynthesis from Space

FLEX is the ESA mission dedicated to studying photosynthesis. The satellite, built by the Thales Alenia Space joint venture (67% Thales, 33% Leonardo), carries FLORIS, the high-resolution spectrometer designed by Leonardo at Campi Bisenzio and the mission's main payload.

FLORIS will analyse the faint light emitted by plants during photosynthesis, breaking it down from red to near-infrared. This signal, invisible to the human eye, will make it possible to measure photosynthetic activity globally and detect stress signals from drought, high temperatures or nutrient scarcity, before visible damage occurs. FLEX data will be merged with Sentinel-3C data for more accurate vegetation measurements, supporting applications ranging from agriculture and forestry to climate monitoring and food security.

Sentinel-3C: Temperature, Oceans and Wildfires Under Observation

Copernicus Sentinel-3C is the third satellite in the Sentinel-3 series of the Copernicus programme. It will provide near-real-time data supporting ocean and weather forecasting, measuring the temperature of seas and land, ocean colour and sea ice thickness.

Among its instruments is SLSTR, the radiometer built by Leonardo at Campi Bisenzio, able to measure sea and land surface temperature with a precision of up to one-tenth of a degree. Two of its channels are optimised to detect wildfires from space, a valuable capability in remote forest areas, where ground-based detection is difficult and costly.

Thales Alenia Space (67% Thales, 33% Leonardo) is the satellite's prime contractor, while Telespazio (67% Leonardo, 33% Thales) supports data processing and access through advanced cloud-based solutions.

Telespazio's Role in Operations

For both missions, Telespazio Germany plays a central role within the Flight Control Team, from preparation through launch and routine operations, ensuring the satellites and their respective payloads — FLORIS for FLEX and SLSTR for Sentinel-3C — operate safely and at maximum performance, covering Data Handling, Attitude and Orbit Control System support, communications, power and thermal systems, and contributing to simulation campaigns and the Launch and Early Orbit Phase (LEOP), in coordination with ESOC and EUMETSAT.

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